They say clothes make the man, but a new study shows they can make the brain, too.

Specifically, what you wear can actually affect your performance on cognitive tests.

Among its many findings, people who put on a white coat that they believed belonged to a doctor made fewer errors on tests of attention than those who put on a white coat they believed belonged to an artist.

The researchers, led by Adam D. Galinsky, a business school professor at Northwestern University's Kellogg School of Management, say that what causes the effect is knowing that physicians have to be careful and pay close attention to their work.

The study is a twist on a growing scientific field called embodied cognition, which has already brought us findings such as the fact that if if you wash your hands, you are less likely to make harsh moral judgments for crimes. The field has also shown us that if you meet someone while holding a hot drink in your hand, you will rate him or her as warmer, but if you meet a person while holding a cold drink in your hand, you'll believe him or her to be colder.

Galinsky calls the effect shown in his study "enclothed cognition" to show that different clothes probably affect our cognition in different ways.

The experiments

The first experiment, which tested selective attention, had 58 undergraduates randomly assigned to wear either a white lab coat or street clothes. They were then tested on how easily they noticed incongruities, such as when the word "red" appeared in green lettering. The lab coat-wearers made half as many errors as those in everyday clothing.

In the second experiment, which tested sustained attention, 74 students wore a doctor's coat, wore a painter's coat, or took the test in a room where they saw a doctor's coat. They then had to look at two very similar pictures side by side and ferret out four minor differences. Again, because their attention was heightened, those in the doctor's coat noticed more differences than those wearing the artist's coat (even though it was the same coat) or those who saw the doctor's coat.

The third experiment tested whether simply seeing the coat could affect behavior. Students either put on a doctor’s coat or a painter’s coat, or were told to look for a long period of time at a doctor’s lab coat on the desk in front of them. Each of the students then wrote essays about the coats. They then took another test on sustained attention.

Again, the group that wore the doctor’s coat got the biggest boost in attention.

Previous experiments have shown that women who go to job interviews dress in a masculine fashion are more likely to be hired, and that a teaching assistant dressed more formally is perceived as more intelligent than one dressed more casually.